A layered structure lithium mixed metal oxide is used as positive electrode active materials in nonaqueous electrolyte secondary batteries, such as a lithium secondary battery. The lithium secondary battery has already been put into practical use as a power source for portable telephones, notebook-sized personal computers, and the like, and also attempted to be used in medium and large size applications, such as applications of use for automobiles or electric power storages.
A conventional method of producing a layered structure lithium mixed metal oxide is described in JP-A-07-326356, which describes a method of obtaining a layered structure lithium nickelate as a layered structure lithium mixed metal oxide by calcining a lithium mixed metal oxide raw material including a mixture of nickel carbonate and lithium nitrate in the presence of an active flux made of LiCl.